Velocipedes have been in existence for well over one hundred years. The earliest forms were literally walkers. The rider propelled the vehicle by walking. This was not preferred because it produced no advantage. There then began development of powered vehicles that produced a mechanical advantage. During this stage there were at least two distinct lines of development. One lead to the common bicycle in use today, that uses pedals to turn a sprocket that engages a chain to turn the rear wheel. This line was well established by 1891. For example, U.S. Pat. No. 456,217 shows a bicycle that is essentially a single speed ladies bicycle of today.
The second line of vehicles uses a reciprocating crank system that rotates the rear wheel or wheels by pushing a pair of pedals in a reciprocating motion. The pedals are connected to a crank system that then turns the wheels. Many different types of vehicles have been developed using this system. U.S. Pat. No. 115,212, for example, shows an early model that uses the reciprocating system simply to drive the vehicle. This line eventually developed into the toy vehicles popular from 1950 on. Others learned to use the reciprocating motion to develop other types of drive mechanisms. One early example of such a vehicle is U.S. Pat. No. 529,717 to Deacon. Here, the rider sits in the seat and pushes the seat backwards and forwards. This action causes the crank to turn the rear wheel. The rider continues to push in this reciprocating manner to keep the vehicle moving. The inventor noted that it is a good form of exercise.
In 1947, U.S. Pat. No. Des. 146,645 to Donaldson was issued. This patent shows a design of a tricycle type vehicle that uses a reciprocating crank drive. However, not only does this vehicle propel the rider forward, it also causes the seat to move up and down as the rider operates the pedals. In 1972, U.S. Pat. No. 3,666,291 to Ortiz shows a more complex, four wheel version or the system that dispenses with the pedals and has the rider operate the vehicle by pushing on the seat. Finally, in 1992, U.S. Pat. No. 5,120,074 to Herman et al. described a four wheel vehicle that uses a modified version of the Donaldson device. The Herman vehicle, as explained in the Herman et al., patent, modified the Donaldson device by extending the frame and by moving the pivot points in an attempt to improve the performance of the vehicle.
Although all of these vehicles operate, they have one serious problem, especially for use as children's toys. The reciprocating components are all exposed and due to the reciprocating nature of the various pivots, the exposed parts can cause serious injury if arms, fingers, feet, toes or clothing get caught in the reciprocating mechanism.